class_docstr: ParameterSystem is a subclass of GroupParameter that manages a tree of 
  sub-parameters with a set of interdependencies--changing any one parameter
  may affect other parameters in the system.
  
  See parametertree/SystemSolver for more information.
  
  NOTE: This API is experimental and may change substantially across minor 
  version numbers. 
code: def updateSystem(self, param, changes):
      changes = [
          ch for ch in changes if ch[0] not in self._ignoreChange
      ]
  
      # resets = [ch[0] for ch in changes if ch[1] == 'setToDefault']
      sets = [ch[0] for ch in changes if ch[1] == "value"]
      # for param in resets:
      # setattr(self._system, param.name(), None)
  
      for param in sets:
          # if param in resets:
          # continue
  
          # if param in self._fixParams:
          # param.parent().setWritable(param.value())
          # else:
          if param in self._fixParams:
              parent = param.parent()
              if param.value():
                  setattr(self._system, parent.name(), parent.value())
              else:
                  setattr(self._system, parent.name(), None)
          else:
              setattr(self._system, param.name(), param.value())
  
      self.updateAllParams()
  
file_path: pyqtgraph/pyqtgraph/parametertree/ParameterSystem.py
imports: from ..None import functions
  from .parameterTypes import GroupParameter
  from .SystemSolver import SystemSolver
label_desc: Use image node_id 3 for calling the ParameterSystem obj's underlying member method code with example usage: obj.updateSystem(param, changes) without return types